Sydney finished the 1-0 winner after supersub Mark Bridge combined lethally with Alex Brosque for a 1-2 that ended up cannoning into the Adelaide net.

The goal came after sustained pressue in the second half, although it looked destined to end in a stubborn stalemate between the two evenly-matched side.

"It was a bit of an arm wrestle but certainly in the second half we fell to pieces and gave the ball away too easily," Vidmar admitted after the match. "The goal came from a turnover and they started to get a fair bit of momentum and it was hard to stop.

"One goal was enough, they kept coming at us in the second half and we couldn't put our foot on the ball, and when it's like that it makes life very hard, you get continued pressure and something has got to give."

Despite United's poor record in Sydney - with just one A-League win so far  - Vidmar insisted the problem was not a mental one, but that they had just been outclassed by Sydney's finishing.

He added: "Although we've only won once here in eight attempts it's not a mental thing at all, they're a good side and showed they will be a very strong side across the course of the year."

Sydney FC coach Vitezslav Lavicka was modest in his appraisal and took comfort from his side's defensive shutout and the level of commitment from his players.

"We have a clean sheet this week, that's an improvement," he said "I appreciated the players' approach - the quality, discipline and every player gave more than 100% for the team."